Method of moving sidewall of watertight floating box

ABSTRACT

In a method of uniting, dividing, repairing, or maintaining under water portions of a floating body, such as a ship hull, the submerged work surfaces are enclosed by a watertight floating caisson box including a bottom structure, extending horizontally and laterally beneath the floating body, and sidewall structures, adjacent the opposite ends of the bottom structure and extending upwardly to engage the sides of the floating body. At least one side structure is guided for movement along the bottom structure relative to the other side structure. The caisson box is pumped free of water to provide a dry working space, and sufficient buoyancy is imparted to the movable side structure to reduce its guiding friction with the bottom structure. The movable side structure is then moved along the bottom structure to a selected working position, after which the buoyancy of the movable side structure is reduced to cause it to sink into watertight pressure contact with the bottom structure.

United States Patent [72] Inventors Mlsataro Muto; l,632,49l 6/1927 Matthiessen et al. l 14/46 Yasuyuki Niimi, both oi Nagasaki, Japan 3,370,563 2/1968 Muto et al. 114/77 [2]] Appl N0. 856,402 3,370,565 2/1968 Takezawa et al. 114/77 [22] F'led Sept 1969 Primary ExaminerMilton Buchler [45] Patented June 22, 1971 Assistant Exammer-F.K. Yee [73] Assignee Mitsubishi Jukogyo Kabushiki Kaisha Attorney-McGlew and Toren Tokyo, Japan [32] Priority Oct. 8, 1968 1331 Java" ABSTRACT: In a method of uniting, dividing, repairing, or [3] l 43/ 73421 maintaining under water portions of a floating body, such as a ship hull, the submerged work surfaces are enclosed by a v watertight floating caisson box including a bottom structure, [54] METHOD OF M ENG SIDEWALL 0F extending horizontally and laterally beneath the floating body,

WATERT'IGHT FLOATING BOX and sidewall structures, ad acent the opposite ends of the hot- 4 Claims, 9 Drawing Figs.

tom structure and extending upwardly to engage the sides of [52] US. Cl 114/77, [he floating body At least one side structure is guided for 6 movement along the bottom structure relative to the other l 1 Int. side structure. The gaisson box is pumped free of water to pro- M 0 San!!! l 78, a working space and sufficient buoyancy is imparted to the movable side structure to reduce its guiding friction 61/64, 66, 63, 3 l33, 22, 24-48, 34 with the bottom structure, The movable side structure is then moved along the bottom structure to a selected working posi- [56] Reiereuces cued tion, after which the buoyancy of the movable side structure is UNHED STATES PATENTS reduced to cause it to sink into watertight pressure contact 808,638 1/ i906 Cunningham 61/68 with the bottom structure.

/2 I as PATENTEU JUN22|97| 3585.954

SHEET 1 [IF 3 FIG. I

FIG.6

IN VE N TORS Mosutorg Mgtq Yosuyulu Nnrm ATTORNEYS SHEET 2 [IF 3 PATENTED JUH22 I97! INVENTORS Mosotoro Mutp Yosuyuki Nllml Mawi {14 ATTORNEYS METHOD OF MOVING SIDEWALL OF WATERTIGI-IT FLOATING BOX BACKGROUND OF THE INVENTION In recent years, the great operating economies combined with the great strides made in shipbuilding technology have given rise toa tendency to build larger and bulkier ships, so that there is today a demand for vessels having capacities of as much as 300,000 to 500,000 D.W.T. each. However, most of the existing ship building ways and docks in Japan and other parts of the world are not capable of building or repairing vessels of such a large size.

In order to construct ships of sizes beyond the capacities of relatively small ship building ways or docks now in use, the socalled uniting-afloat method has been proposed. In this method, a hull is built in two or more sections having dimensions suitable for the existing ship building ways or docks, the sections are launched separately, and the sections are then welded or otherwise joined together while afloat in the water.

The most serious of the problems involved in the unitingafloat method, which naturally causes the floating sections to be partly submerged by their own weight, is how to unite the submerged portions safely with full reliability instructural strength. In an attempt to solve this problem, it has been proposed to cover the submerged portions of the sections to be united together in a watertight fashion with a boxlike structure, such as a caisson having a U-shaped cross section, and then to pump out water from the interior of the caisson to provide a dry working space in which workers can perform the necessary operations, such as, for example, the joining of the separate hull sections together and the inspection of the united hull.

The watertight floating boxes proposed for this purpose have fixed widths and, for this reason, each box can be used repeatedly only with ships of the same overall beam or width. Where many vessels of different beams or widths are to be built, watertight boxes having corresponding dimensions must be fabricated, with inconvenience and disadvantages from the economic standpoint.

Since such a box is fabricated in advance to a width in complete agreement with the beam of the vessel to which it is to be applied, there is almost no space provided between the sidewalls of the box and the side platings of the hull, and this makes it very difficult to fix the box to the hull and to remove the box from the hull.

SUMMARY OF THE INVENTION This invention relates to providing a dry, watertight working space along submerged portions of a large floating body, such as a ship or floating dock, to be worked upon and, more particularly, to a novel and improved method of adjusting a watertight floating caisson box to such floating bodies having various beams and widths.

The objective of the present invention is to provide watertight floating boxes of the type mentioned and which are free from the drawbacks of the conventional boxes and can be used in common with various vessels and other floating bodies of different widths, the watertight boxes being easy to attach to the floating bodies and easy to disengage from the floating bodies. In accordance with the invention, the submerged portion of a floating body, such as a ship hull, to be divided, united, repaired, or otherwise handled while afloat, is covered with a watertight caisson box body comprising, essentially, a bottom structure extending horizontally and transversely of the bottom of the working surfaces of the floating body and sidewall structures provided near both ends of the bottom structure. At least one of the sidewalls is movable transversely relative to the floating body. The inside of the caisson box is pumped free of water, thereby providing a dry working space along the working surfaces of the floating body. The movable sidewall structure is given a sufficient buoyancy to lessen its friction with the bottom structure as it is moved transversely of the latter, through guide roller means provided between the movable side structure and the bottom structure. The buoyancy is decreased after the sidewall structure has been moved to a desired position, so that the sidewall structure can sink onto the bottom structure to establish a watertight pressure contact therewith.

An object of the present invention is to provide a method of using watertight floating boxes for working on submerged surfaces of floating bodies.

Another object of the invention is to provide such a method which is free of disadvantages of presently used methods.

A further object of the invention is to provide such a method in which one watertight floating box can be used with various vessels of different beams, or various floating bodies of different widths.

Another object of the invention is to provide such a method in which a watertight floating box is easy to attach to a floating body and to detach from the floating body.

A further object of the invention is to provide such a method in which a movable sidewall of a watertight floating box is initially given a sufficient buoyancy to lessen its friction with the bottom structure of the floating box, adjusted along the bottom structure to a predetermined position, and decreased in buoyancy to establish a watertight pressure contact with the bottom structure.

For an understanding of the principles of the invention, reference is made to the following description ofa typical embodiment thereof as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a side elevational view of a watertight floating box as applied to the hull of a vessel under construction, in accordance with the invention method;

FIG. 2 is a transverse sectional view corresponding to FIG.

FIG. 3 is a top plan view ofthe floating box;

FIG, 4 is a section taken on the line IV-IV of FIG. 3;

FIG. 5 is a sectional view taken on the line V-V of FIG. 3;

FIG. 6 is a sectional view taken on the line VIVI of FIG. 3;

FIG. 7 is a perspective view of the movable sidewall and the associated parts of the bottom structure;

FIG. 8 is a top plan view illustrating the means for moving the movable sidewall; and

FIG. 9 is a sectional view on the line IX-IX of FIG. 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the several figures of the drawings, reference numerals l and 2 designate, respectively, the forebody and the afterbody of a ship hull, the forebody and the afterbody having been built separately on relatively small ship building ways or other existing facilities and separately launched to be united while afloat, The work of uniting the two hull sections 1 and 2 is effected in a watertight floating box embodying the invention and which comprises a U-shaped caisson having inner dimensions larger than the beams of the adjoining portions of the ships or hull sections 1 and 2 to be united. Box 3 has a plurality of ballast tanks 4 capable of having water pumped thereinto or pumped therefrom to maintain box 3 at its proper draft and trim, in the manner of a small floating dock.

Watertight floating box 3 generally comprises a bottom structure 5 which extends horizontally under the bottom of the hull and transversely thereof, and sidewall structures 6 and 7 located near respective opposite ends of bottom structure 5. The sidewall structures extend substantially vertical with respect to the side strakes of the hull, and at least one of the sidewall structures, for example the sidewall structure 6 in the particular embodiment being described, is movable along bottom structure 5 transversely of the hull resting on the bottom structure. Sidewall structures 6 and 7 are formed with curved portions I0 and II, respectively, opposite the bilge circles 8 and 9 of the hull sections, the curvatures of portions 10 and 11 conforming to the curvatures of bilge circles 3 and 9. Thus, when sidewall structure 6 is drawn inwardly with respect to the opposing side of the hull, the entire inner surfaces of the sidewalls 6 and 7 are in contact with the side strakes of the vessel.

In the middle of the watertight floating box 3, and above bottom structure and between sidewall structures 6 and 7, there is provided an operating space ll2 extending transversely of the vessel and having a sufficient height and width to permit operators to work on the hull sections in the erect or standing position.

Movable sidewall structure 6 is provided with ballast tanks 13 arranged to have water pumped thereinto or pumped therefrom to adjust the buoyancy of sidewall structure 6. This sidewall structure fits in a recess 14 which is substantially U shaped in cross section and which extends a suitable distance along bottom structure 5. At the bottom of sidewall structure 6 opposite to the surface of recess 14 there are provided watertight packings l5 and 15'.

Guide grooves 16 and 16' are formed on opposite sides of bottom structure 5 to facilitate movement of sidewall structure 6 therealong. Support arms 17, 17' extend outwardly from opposite sides of movable sidewall structure 6, as if to hold bottom structure 5 with both hands. Near the lower ends of the support arms 17 and 17', there are provided respective pairs of guide rollers 16, 18 and 18', 18' which lit in the respective guide grooves 16 and 16.

As best seen in FIGS. 8 and 9, winches 19 are installed on the unsubmerged portion, near the top, of movable sidewalls 6. Wires 20, extended from winches 19, are connected at ends 21 to points in the vicinity of the front end of sidewall 6, through guide pulleys 22 and 23 on sidewall 6, and also through guide pulleys 24 on bottom structure 5. The opposite ends 25 of wires are connected to points in the vicinity of the rear end of sidewall structure 6, through guide pulleys 26 and 27 on guide wall structure 6 and through guide pulleys 28 on bottom structure 5, so that sidewall structure 6 can be driven transversely of the ship's hull by operation of winches 19.

In moving sidewall structure 6, ballast tanks 13 therein are initially pumped free of water ballast to provide sufficient buoyancy to set sidewall structure 6 afloat and bring watertight packings 15 and 15' out of contact with the bottom recess 14 thereby to reduce the frictional resistance, at the time of adjustment of sidewall structure 6 along bottom struc ture 5, to zero. Sidewall structure 6 is guided along bottom structure 5 by means of the pairs of guide rollers 18, 18 and 18, 13.

On the surface of watertight floating box 3 facing the outside plating of the hull sections, there are laid continuous strips of watertight packings 29, 29' which extend from bottom structure 5 up to the stationary sidewall structure 7, and also continuous strips of watertight packings 30 and 30 which extend from bottom structure 5 up to the movable sidewall structure 6. These watertight packings 29, 29' and 30, 30 may take the form of strips, or may take the form of tubes which are expandable with a pressure fluid. They may also take any other form which is effective to establish a watertight seal between the outside plating of the hull and the watertight floating box.

As shown, watertight packings 29, 29 and 30, 30' are provided as two pairs, so that the inner packing in each pair can prevent spatter of any sea water that may leak through the outer packing into the working space 12, thus avoiding any hindrance to working operations inside space 12. The sea water that has leaked in through the outer packings is led through bilge pipes 31 into drain ducts 32 and 32' of working space 12, and is drained out of the watertight box by a drain pump which has not been shown. in the operation of uniting, for example, the forebody 1 and the afterbody 2 of a ship hull, while these bodies, which have been built on existing ship ways or the like and launched separately,are afloat, fore- 1 and afterbody 2 are first maintained, at their proper draft or trim through adjustment of the water ballast in the ballast tanks provided in these hull sections. The adjoining parts of the two sections are matched, as shown in HO. 1, and then watertight floating box 3 is brought to a point immediately ahead of or immediately astern of the hull, as by a tug boat or a sea crane. Following this, water is controllably pumped into the ballast tank 45 of watertight floating box 3 until box 3 as a whole is submerged to a desired draft. The box is then moved longitudinally at the hull, as by towing, so that it is positioned immediately beneath the portions of the hull to be joined together. However, prior to this stage of the operation, the movable sidewall 6 of box 3 has been moved outwardly to a point at which the interior dimensions of box 3 are somewhat greater than the beam or width of the hull.

When box 3 is properly aligned longitudinally of the hull, a force is exerted thereon, for example by a tug boat, so that the inner wall surface of the stationary sidewall structure 7 is brought into contact with the outside plating of the hull. At the same time, ballast tanks 4 of box 3 are gradually pumped free of water ballast. As a result, box 3 floats up and bottom structure 5 and stationary sidewall 7 are kept in pressure contact with the outside plating of the hull, and in a watertight fashion through the packings 29, 29.

Next, ballast tanks 13 in movable sidewall structures 6 are pumped free of water ballast to provide increased buoyancy to movable sidewall structure 6. Winches 19 then are started to move sidewall 6 transversely of the hull, whereby sidewall 6, with a reduced friction with respect to bottom structure 5, is guided by guide rollers 18, 18 and 18, 18 along bottom structure 5 and is eventually brought into watertight contact with the outside plating of the hull, through the medium of interpose packings 30 and 30'.

Water is then pumped into ballast tanks 13 to reduce the buoyancy of sidewall structure 6 immediately before such watertight contact, so that sidewall structure 6 sinks onto bottom structure 5 and thus is kept in watertight contact with the generally U-shaped recess 14 of the latter through packings l5 and 15'. Consequently, if the water in working space 12 of box 3 is pumped out by the pump which has not been illustrated, a dry working space 12 is defined along those portions of the hull which are to be joined together, permitting operators to proceed with the joining work, inspection, and other operations quickly and safely from outside the hull.

Although a particular watertight floating box in accordance with the invention, and a particular method of using such a box in the uniting-afloat of hull sections, have been described, it will be clear that this invention is not limited thereto, as boxes embodying the invention may be employed equally well in the cutting, repairing, or other work on underwater portions of ships or other floating bodies. In the broader sense, the applications of the invention may even include successive movements of such boxes in the longitudinal direction of the ships or the like for repair, inspection, coating, or other operations, thus eliminating the necessity of dry docks which have hitherto been considered indispensable for such operation carried out on a floating body.

In brief, the present invention provides a method of moving a sidewall structure of a watertight floating box, which comprises covering, in watertight fashion, the underwater portions of a ship or other floating body to be divided, united, repaired or otherwise handled afloat, with a box body, such as a caisson. This body consists essentially of a bottom structure extending horizontally along the bottom of the portions of the floating body upon which work is to be performed, and sidewall structures provided near respective opposite ends of the bottom structure. At least one of the sidewall structures is movable transversely of the floating body. The inside of the watertight box is pumped free from water, thereby defining a working space along the portions of the floating body upon which work is to be performed.

The movable sidewall structure is initially given a sufficient buoyancy to lessen its friction with the bottom structure, through guide roller means provided between the sidewall structure and the bottom structure. The buoyancy of the movable sidewall structure is decreased after the latter has been moved to a desired position so that the sidewall structure can sink onto the bottom structure to establish a watertight pressure contact therewith. Thereby, watertight floating boxes of the type described can be adjusted in width with extreme ease to fit various floating bodies with different widths, while achieving a sufficient and reliable water sealing effect.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

What we claim is:

l. A method of uniting, dividing, repairing, or maintaining under water or submerged portions of a floating body, such as a ship hull, while the body is afloat, said method comprising the steps of enclosing the submerged work surface of the floating body by a watertight floating caisson box including a bottom structure extending horizontally and laterally beneath the floating body and sidewall structures adjacent the opposite ends of the bottom structure and extending upwardly to engage the sides of the floating body, with at least one sidewall structure being guided for movement along the bottom structure relative to the other sidewall structure; pumping the caisson box free of water to provide a dry working space along the submerged work surfaces of the floating body; imparting, to

the movable one sidewall structure, sufficient buoyancy to reduce its guiding friction with the bottom structure; moving the movable one sidewall structure along the bottom structure to a selected working position; and then reducing the buoyancy of the movable one sidewall structure to cause it to sink into watertight pressure contact with the bottom structure.

2. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim I, including the step of providing guide ways on the bottom structure; and providing guide roller means on the movable one sidewall structure in engagement with the guide ways on the bottom structure.

3. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim 1, including the step of connecting winch and cable means between the bottom structure and the movable one sidewall structure for adjustment of the movable one sidewall structure along the bottom structure.

4. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim 1, including the step of providing pairs of gaskets extending in spaced parallel relation along those surfaces of the caisson box engageable with the work surfaces of the floating body to provide sealing engagement with the work surfaces, 

1. A method of uniting, dividing, repairing, or maintaining under water or submerged portions of a floating body, such as a ship hull, while the body is afloat, said method comprising the steps of enclosing the submerged work surface of the floating body by a watertight floating caisson box including a bottom structure extending horizontally and laterally beneath the floating body and sidewall structures adjacent the opposite ends of the bottom structure and extending upwardly to engage the sides of the floating body, with at least one sidewall structure being guided for movement along the bottom structure relative to the other sidewall structure; pumping the caisson box free of water to provide a dry working space along the submerged work surfaces of the floating body; imparting, to the movable one sidewall structure, sufficient buoyancy to reduce its guiding friction with the bottom structure; moving the movable one sidewall structure along the bottom structure to a selected working position; and then reDucing the buoyancy of the movable one sidewall structure to cause it to sink into watertight pressure contact with the bottom structure.
 2. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim l, including the step of providing guide ways on the bottom structure; and providing guide roller means on the movable one sidewall structure in engagement with the guide ways on the bottom structure.
 3. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim 1, including the step of connecting winch and cable means between the bottom structure and the movable one sidewall structure for adjustment of the movable one sidewall structure along the bottom structure.
 4. A method of uniting, dividing, repairing, or maintaining underwater or submerged portions of a floating body, as claimed in claim 1, including the step of providing pairs of gaskets extending in spaced parallel relation along those surfaces of the caisson box engageable with the work surfaces of the floating body to provide sealing engagement with the work surfaces. 